How much weight should we give to unpleasant revelations about the private lives of thinkers? It partly depends on what kind of thinker we’re talking about. When it was discovered a few years after his death in 1983 that Paul de Man had written for Nazi-controlled newspapers in Belgium, a debate began on whether this had any bearing on the deconstruction he propounded. The new revelations rooted out by Evelyn Barish in her biography of de Man last year – bigamy, fraud and an unserved prison sentence – further fuelled the discussion.[*] Similar questions circle around Heidegger: it had always been known that he was a member of the Nazi Party, but his Black Notebooks, recently published in Germany, contained new evidence of anti-Semitism. Revelations like these trouble the writers’ acolytes, but it isn’t clear that they damage their work (not clear, but possible: a case has been made that there are connections between Heideggerian Dasein and Nazi ideology). Heidegger, after all, like de Man, made no claim to be a philosopher of ethics: he claimed in his ‘Letter on Humanism’ that ethics begins ‘to flourish only when originary thinking comes to an end’.

Yet the charge of hypocrisy can legitimately be levelled at any ethical philosopher, ancient or modern, who doesn’t abide by his own teachings. A mathematician who solves a famous problem may be a known scoundrel and liar, but mathematicians don’t come up with ethical injunctions for others to follow. If we were to discover that despite his exaltation of the rational part of the soul, Plato spent his days getting drunk and ogling young boys in the gymnasion, what would we think of the moral philosophy he puts in Socrates’ mouth? Still, simply noting the presence of hypocrisy doesn’t answer the question of whether hypocrisy matters, or when it should make a difference. It merely raises more questions: if an author doesn’t follow his own recipe for the happy moral life, can it still be a good recipe? If he’s too weak to follow it, can we assume others will be stronger? Should we be grateful that he can state philosophical ideals even if he can’t live them? Should we try to make sense of the situation by assuming that no one would willingly think of themselves as a hypocrite, but would believe there were extenuating circumstances in their own case?

We don’t get many opportunities to try out these options. Summon up a list of great ethical thinkers: they are all exemplary figures, even if that is because their lives were cleaned up ex post facto by the tradition that passed on their teachings. The Buddha was moved by human suffering to seek enlightenment; Socrates was self-abnegating and wise in his knowledge of his own lack of wisdom; Confucius left politics to teach the importance of duty, self-cultivation and personal example. They all seem to have abided by their own teachings, which has made the teachings more persuasive – imagine a hypocritical Jesus, and you get a sense of the devastation that would be wrought on the faithful. Even Marcus Aurelius belongs in this company: he held a degree of political power unusual for a moral philosopher but his apparently private notes to himself, the Meditations, show him to be troubled by the exercise of empire and keen to rid himself of any signs of a weakness for wealth or power.

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